Well, I started the process at work with Apache Jena as the target, If I change target I have to start the process over. Unless there is a very strong reason to move to Commons RDF I would prefer to stay with Jena.
Given that we want to run SPARQL queries over the data I think we want to stay with Jena. Claude On Mon, Oct 31, 2016 at 2:23 PM, Stian Soiland-Reyes <st...@apache.org> wrote: > Do you think it would make sense to do a Cassandra Commons RDF API binding > for Graph or Dataset..? Or would that be too high level? > > The streaming part would fit well there I think. > > Commons RDF 0.3.0 is under vote now, adding Quad, Dataset and "RDF" as the > factory interface. > > https://commonsrdf.incubator.apache.org/apidocs/index.html? > org/apache/commons/rdf/api/package-summary.html > > But it could make more sense as a Jena DatasetGraph so it can be used by > sparql queries etc. (And then exposed as Commons RDF Jena bindings if one > so wanted) > > On 31 Oct 2016 1:41 pm, "Claude Warren" <cla...@xenei.com> wrote: > > > Andy, > > > > This seems like a good approach but does not appear to be in the Jena > code > > base, which I suppose is your comment about an approach to developing > work. > > > > Does it make sense to create git clones that contain the new work? Or > > perhaps branches? > > > > Do you have a suggestion or direction you would like to see this go? > > > > Claude > > > > > > > > On Fri, Oct 28, 2016 at 2:35 PM, Andy Seaborne <a...@apache.org> wrote: > > > > > Claude, > > > > > > These may help: > > > > > > I have been thinking about an interface that is more oriented to the > > > storage than the full DatasetGraph. > > > > > > StorageRDF breaks down all the operations into those on the default > graph > > > and those on named graphs. For just a graph, simply ignore the named > > graph > > > operations. > > > > > > https://github.com/afs/AFS-Dev/blob/master/src/main/java/pro > > > jects/dsg2/storage/StorageRDF.java > > > > > > There is an adapter to the DatasetGraph hierarchy (which is needed for > > > SPARQL): > > > > > > https://github.com/afs/AFS-Dev/blob/master/src/main/java/pro > > > jects/dsg2/DatasetGraphStorage.java > > > > > > If you want to only use existing classes, DatasetGraphTriplesQuads is > the > > > place to start - used by TIM and TDB - yuo can implement without > needing > > > quads/named graphs. Again, simply ignore (throw > > > UnsupportedOperationException for the named graph calls). > > > > > > Going the graph route could lead to rework later on for any kind of > > > performance issues because find(S,P,O) is so narrow and precludes union > > > default graph except by brute force. DatasetGraph work with the SPARQL > > > execution engine. > > > > > > We still need to discuss how best to approach developing work - it > should > > > not get sucked up by the release cycle. > > > > > > Andy > > > > > > > > > On 26/10/16 19:21, Claude Warren wrote: > > > > > >> My plan is to start with a Graph implementation. We expect to write 3 > > >> tables: SPO, POS, OPS (I think). Currently we don't have an easy way > to > > >> handle find( ANY, ANY, ANY) so I suspect we will just start with > > >> permitting > > >> a column scan on Cassandra. > > >> > > >> I have not looked at DynamoDB but as I recall there are significant > > >> differences under the hood. > > >> > > >> I expect that we will move on to a custom model or query engine to get > > the > > >> best performance but that is not what we are planning for the first > cut. > > >> > > >> I am still waiting for management approval to do this at work .... > > >> sometimes it takes longer to get the paperwork done than it does to > > design > > >> the thing. > > >> > > >> > > >> Claude > > >> > > >> On Mon, Oct 17, 2016 at 6:39 PM, Paul Houle <paul.ho...@ontology2.com > > > > >> wrote: > > >> > > >> I like DynamoDB as a target for this sort of thing. There are many > > >>> tasks which are small-scale yet critical where it would otherwise be > > >>> hard to provide a distributed and reliable database. Put that > together > > >>> with Lambda, which does the same for computation, and you are > cooking > > >>> with gas. > > >>> > > >>> I wrote a 1-1 translation of DynamoDB documents to RDF that I use > > >>> throughout an application; the code is DynamoDB idiomatic in every > > way, > > >>> just the application reads and writes (a constrained set of) RDF > > >>> documents. > > >>> > > >>> Right now I dump the documents from the DynamoDB system into a triple > > >>> store when I want a panoptic view, but with a distributed graph like > > >>> that would mean being able to run SPARQL queries against DynamoDB > > >>> directly. > > >>> > > >>> There are many products in the same family as Cassandra and DynamoDB > > and > > >>> it would be good to think through the math so we can approach them > all > > >>> in a similar way. > > >>> > > >>> -- > > >>> Paul Houle > > >>> paul.ho...@ontology2.com > > >>> > > >>> On Mon, Oct 17, 2016, at 12:31 PM, A. Soroka wrote: > > >>> > > >>>> Yep, > > >>>> > > >>>> http://iswc2011.semanticweb.org/fileadmin/iswc/Papers/ > > >>>> > > >>> Workshops/SSWS/Ladwig-et-all-SSWS2011.pdf > > >>> > > >>>> > > >>>> indicates that they are indexing by subject. As someone who has > > >>>> implemented LDP, that is definitely the approach that makes sense > > there. > > >>>> > > >>>> --- > > >>>> A. Soroka > > >>>> The University of Virginia Library > > >>>> > > >>>> On Oct 17, 2016, at 12:20 PM, Andy Seaborne <a...@apache.org> > wrote: > > >>>>> > > >>>>> IIRC It stores CBDs indexed by subject so it is the "other" model > to > > >>>>> > > >>>> Rya. Better for LDP (??). > > >>> > > >>>> > > >>>>> Andy > > >>>>> > > >>>>> On 17/10/16 15:41, A. Soroka wrote: > > >>>>> > > >>>>>> There's also: > > >>>>>> > > >>>>>> https://github.com/cumulusrdf/cumulusrdf > > >>>>>> > > >>>>>> in a similar vein (RDF over Cassandra). Not sure what kind of > > >>>>>> > > >>>>> particular uses it expects to support. > > >>> > > >>>> > > >>>>>> --- > > >>>>>> A. Soroka > > >>>>>> The University of Virginia Library > > >>>>>> > > >>>>>> On Oct 17, 2016, at 7:02 AM, Andy Seaborne <a...@apache.org> > wrote: > > >>>>>>> > > >>>>>>> Hi Claude, > > >>>>>>> > > >>>>>>> There is certainly interest from me. > > >>>>>>> > > >>>>>>> What the best thing to do depends on various factors. By putting > > it > > >>>>>>> > > >>>>>> in extras I presume you mean it gets added to the release? That > is > > >>> not the > > >>> only way forward. > > >>> > > >>>> > > >>>>>>> An important aspect of Apache is "Community over code" - will > there > > >>>>>>> > > >>>>>> be a community around this code? Is that community the same, or > > >>> significant overlap, as the Jena community? > > >>> > > >>>> > > >>>>>>> There are various reasons for wanting RDF over a column store - > > >>>>>>> > > >>>>>> which use cases are the most important for this work? > > >>> > > >>>> > > >>>>>>> They lead to different ways of using Cassandra. For example, > > >>>>>>> > > >>>>>> Rya(incubating) uses Accumulo tables as indexes, and partial scans > > of > > >>> the > > >>> table is streaming. Other systems try to use the columns for > > properties, > > >>> possibly more useful for LDP style than SPARQL. > > >>> > > >>>> > > >>>>>>> Andy > > >>>>>>> > > >>>>>>> On 15/10/16 18:38, Claude Warren wrote: > > >>>>>>> > > >>>>>>>> Howdy, > > >>>>>>>> > > >>>>>>>> We have a project at work that is implementing Jena Graph on > > >>>>>>>> > > >>>>>>> Cassandra. I > > >>> > > >>>> am wondering if there is enough interest here to accept it as a > > >>>>>>>> contribution. I was thinking that it might fit in the Extras > > >>>>>>>> > > >>>>>>> category. > > >>> > > >>>> > > >>>>>>>> I can not promise release of the code yet as I have to present > it > > >>>>>>>> > > >>>>>>> to our > > >>> > > >>>> internal Intellectual Property group first. > > >>>>>>>> > > >>>>>>>> Thoughts? > > >>>>>>>> > > >>>>>>>> Claude > > >>>>>>>> > > >>>>>>>> > > >>>>>> > > >>>> > > >>> > > >> > > >> > > >> > > > > > > -- > > I like: Like Like - The likeliest place on the web > > <http://like-like.xenei.com> > > LinkedIn: http://www.linkedin.com/in/claudewarren > > > -- I like: Like Like - The likeliest place on the web <http://like-like.xenei.com> LinkedIn: http://www.linkedin.com/in/claudewarren
